Choosing troops for a Trafalgar boarding party

If you could choose any land regiment for a Trafalgar-era boarding party, whom would you select?

For Britain, the Royal Marines are the first choice. The key requirement is troops suited to violent close-quarters fighting aboard ship.

For a British force, the Royal Marines are the first choice. The Spanish and French examples favour proven soldiers and specialist light infantry rather than formations chosen for prestige alone. Imperial Russian infantry receive a less favourable judgment because their training was considered unsuitable for fighting aboard ship. The consistent requirement is the ability to fight effectively in confined spaces. Specialist infantry qualities mattered when a naval action became a boarding fight.